Accelerate your SEO efforts on the fly. SEOquake is a free plugin for browsers that provides you with key SEO metrics for a specific page, along with other useful tools such as SEO Audit and many others.

RDS seo toolbar (pr, dmoz, alexa, seomoz ... ) – is a useful tool for fast analysis of website and page SEO indicators, designed for webmasters and optimizers. And also with a range of useful functions for ordinary users.

See Google Pagerank (PR) and Alexa rank for each website you visit. Simple and customizable. You can see and use everything the toolbar offers, or strip it down to the bare essentials and place it in the status bar. Simple, quick, and very useful.

Pixel Perfect is a Firefox extension that allows web developers and designers to easily overlay a web composition with semi-transparent layers (images). These layers can be consequently used for per pixel comparison between the page and a layer.

The all in one toolbar(item). Houses and manages bigger amounts of buttons (Clear Cache, Clear Cookies, ...), Menus (User Agent spoof...) and checkboxes (Javascript, Flash, ...). Extensible from online-database or with self created buttons.

Record, bookmark and replay your browser activities in a snap with DéjàClick. Designed for Firefox, DéjàClick can handle the most complex websites - including AJAX, Flash, forms and more. With a single click you can repeat your most common tasks.

Toggle Web Developer Toolbar has been specially designed for web developers to provide easy to use methods to toggle Web Developer toolbar so that they can preserve their browser view area when they do not use Web Developer toolbar.

The extension generates a documentmap or index of any web document structured with headings and/or with sections in HTML 5. It shows the headings structure, the errors in the structure (ie. incorrect levels), and it works as HTML5 Outliner too.